Based on a Navier-Stokes/full potential/free wake solver, a new hybrid method was developed for efficient predictions of the three-dimensional viscous flowfield of a helicopter rotor under both hover and forward flight conditions. The developed flow solver was composed of three modules: 1) a compressible Navier-Stokes analysis to model the viscous flow and near wake about the blade, 2) a compressible potential flow analysis to model the inviscid isentropic potential flow region far away from the rotor, and 3) a free wake model to account for tip vortex effects once the tip vortex leaves the viscous flow region and enters the potential flow region. In this hybrid method, a moving embedded grid methodology was adopted that accounts for rigid blade motions in rotation, flapping, and pitching. A dual-time method was employed to fulfill the calculation of the unsteady flowfields of helicopter rotors, and a third-order upwind scheme (MUSCL) and flux-difference splitting scheme without introducing artificial viscosity were used to calculate the flux. To search suitable donor elements in embedded grids to pass information between the viscous flow and potential flow zones, a new searching scheme was implemented. The sectional pressure distributions of a UH-60A helicopter rotor and an AH-1G model rotor in hover and forward flight, with and without the wake model, were calculated, and the developed hybrid model was validated by comparing with available experimental data. The simulated steady and unsteady lifting results of a model rotor with three different blade-tip planforms demonstrate the benefits of the curvilinear swept tip and constant swept tip in suppressing supercritical flows.